One of the challenges test-takers encounter on Sentence Correction questions is the tendency of question writers to structure sentences in a way that departs from the way we typically write or speak. Take a simple example: “My books are on the table,” could also be written as “On the table are my books.” If you’re like me, you cringe a little bit with the second option – it sounds starchy and pretentious, but it’s a perfectly legitimate sentence, and an example of what’s called “inverted structure.”

In a standard structure, the subject will precede the verb. In an inverted structure, the subject comes after the verb. The tipoff for such a construction is typically a prepositional phrase – in this case, “on the table ,” followed by a verb . It is important to recognize that the object of the prepositional phrase, “table,” cannot be the subject of the verb, “are,” so we know that the subject will come after the verb.

Let’s look at an example from an official GMAT question:

The Achaemenid empire of Persia reached the Indus Valley in the fifth century B.C., bringing the Aramaic script with it, from which was derived both northern and southern Indian alphabets.

(A) the Aramaic script with it, from which was derived both northern and (B) the Aramaic script with it, and from which deriving both the northern and the (C) with it the Aramaic script, from which derive both the northern and the (D) with it the Aramaic script, from which derives both northern and (E) with it the Aramaic script, and deriving from it both the northern and

The first thing you might notice is the use of the relative pronoun “which.” We’d like for “which” to be as close to as possible to its referent. So what do we think the alphabets were derived from? From the Aramaic script.

Notice that in options A and B, the closes referent to “which” is “it.” There are two problems here. One, it would be confusing for one pronoun, “which,” to have another pronoun, “it,” as its antecedent. Moreover, “it” here seems to refer to the Achaemenid Empire. Do we think that the alphabets derived from the empire? Nope. Eliminate A and B. Though E eliminates the “which,” this option also seems to indicate that the alphabets derived from the empire, so E is out as well.

We’re now down to C and D. Notice that our first decision point is to choose between “from which derive” and “from which derives.” This is an instance of inverted sentence structure. We have the prepositional phrase “ from which ,” followed immediately by a verb “derive ” or “derives.” Thus, we know that the subject for this verb is going to come later in the sentence, in this case, the northern and southern alphabets. If we were to rearrange the sentences so that they had a more conventional structure, our choice would be between the following options:

C) Both the northern and the southern Indian alphabets derive from [the empire.]

or

D) Both northern and southern Indian alphabets derives from [the empire.]

Because “alphabets” is plural, we want to pair this subject with the plural verb, “derive.” Therefore, the correct answer is C.

Takeaway: anytime we see the construction “ prepositional phrase + verb ,” we are very likely looking at a sentence with an inverted sentence structure. In these cases, make sure to look for the subject of the sentence after the verb, rather than before.